1. Field of the Disclosure
The present disclosure relates in general to valves for hydrocarbon recovery wells, and in particular to actuators to actuate valves.
2. Description of Related Art
Actuators can be a hydraulic, piston type actuator, or actuators can be a pneumatic piston or diaphragm type actuator. In conventional diaphragm actuators, a diaphragm is moved in response to pressure media, such as gas or other fluids, urging the diaphragm toward a gate valve. The diaphragm is supported by a support plate. When the diaphragm is urged downward with the pressure media, it urges the support plate downward, which then transfers the downward force via a stem to the valve to open or close the valve, as applicable.
Actuators can be secured to different types of valves to move a valve between open and closed positions. As an example, a gate valve is a valve having a body and a bore through the body. A gate is positioned transverse to the body, and moves linearly to obstruct flow through the bore or allow flow through the bore. Some gates have an aperture that aligns with the bore to allow flow. The gate can be normally open, and thus the gate is closed when it is moved linearly to push the aperture out of alignment with the bore. Alternatively, a gate can be normally closed, and thus the gate is opened when it is moved linearly to position the aperture in alignment with the bore. Regardless of whether the gate is normally open or normally closed, the gate is moved, or actuated, by a valve actuator.
When additional force is needed to operate a valve, more than one actuator can be used to operate the valve. However, multiple actuators can take up more space than is available at the site of the valve, and operating more than one actuator at a time can be cumbersome and difficult to coordinate.